One love story in Hunter x Hunter could be between Gon and Killua. Their friendship has strong undertones of love. They care deeply for each other, always looking out for one another during their adventures. Killua is willing to go to great lengths to protect Gon, and Gon's unwavering trust in Killua is a form of love in this harsh world of Hunters.
A possible scenario is that a female Hunter falls in love with an older, more experienced Hunter. She admires his skills and wisdom. He initially sees her as a young novice but is gradually charmed by her determination and fresh perspective. They start to train together and during those long training sessions, love blossoms.
Since there's no official ending yet, it's hard to say. But if it follows the pattern of the series so far, it could be very satisfying. The series has been great at character development, so seeing all the characters reach a proper conclusion would be great.
Well, Hisoka's origin story in Hunter x Hunter is quite interesting. He hails from Meteor City, a place that's more like a dumping ground for the unwanted. Growing up there, he was exposed to all sorts of things that normal people wouldn't experience. His love for fighting strong opponents probably stems from the fact that in Meteor City, strength was the only way to get what you want. Hisoka's nen abilities are also a product of his environment. He's constantly evolving and seeking new challenges, which is likely a trait he developed while growing up in a place where only the fittest survive.
Well, Killua is a complex and interesting character. A love story could start with the reader meeting Killua during his adventures. Maybe they first cross paths in a dangerous situation where Killua uses his assassin skills to protect the reader. This initial encounter sparks an interest in both of them. As they spend more time together, Killua begins to open up about his past, his family and his fears. The reader, in turn, offers him understanding and support, which he has rarely received. Their relationship gradually deepens into love as they share many more experiences and grow together.
The Hunter x Hunter manga is unfortunately not complete. The author has faced various issues that have led to intermittent breaks and an unresolved storyline.